The gap between results from sham-controlled trials and trials using other controls in acupuncture research-The influence of context

In chronic pain studies involving acupuncture treatments, the size of the effect between acupuncture and a sham acupuncture control is usually small. By contrast, when acupuncture is compared to an active control group (usual care or standard treatment), the size of the effect is generally moderate and clinically relevant. Factors such as treatment setting, the expectations of patient and practitioner, and the interaction between patient and practitioner differ for different treatments and may influence the study outcome. In acupuncture, these factors seem to play a role. Acupuncture research is helpful in stimulating placebo research and illuminates a variety of aspects that influence the placebo response. The influence of different types of patient-practitioner interaction and their underlying mechanisms seem to be a clinically relevant area for future research, but should be researched in less complex placebo models than sham acupuncture. (c) 2012 Elsevier Ltd. All rights reserved.